Staggering + building a 20" notch?
#1
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Will a 20" notch be asking for trouble on a 90's 38' Scarab Thunder with standard Bravo 1's?
I have a 38' Scarab Thunder on which I will rebuild the transom and engine room stringers next year. Looking down at the engines I realize that there's so much room in front of the Engines that if I extend the engine compartment by making a 20" notch (and move the transom back 20") it will be possible to mount the engines in a staggered configuration rather than side by side (the way it looks today). There are a number of reasons this could be a great advantage:
+ Most of the advantages of staggered engines (More room to work on the engines, Drives closer to the center = better propeller grip with lower mounting height, More weight moved closer to the centerline, etc)
+ A 20" notch enabling the x-dimension to be raised, although the drives will be deeper down towards the V (higher top speed)
+ Better angle of attack for the drives to work with (easier to trim the boat, easier to get on plane, and a higher top speed)
+ Still the same cockpit space, as I will only use the existing space in front of the engines
+ No shifting of the COG, as the extension would be in the shape of a notch
There are also a number of negatives of course:
- More work
- Less maneuverability when docking
- The possible risk of unpredicted negatives in handling, as this has not been done previously...
What do you think? Should I do it, or should I stick to just rebuilding everything the way it looks, and follow the old saying "If it ain't broken, don't fix it"...?
The biggest benefits in my world would be accessibility. Extension boxes and short lowers cost to much (due to import taxes and a poor dollar exchange rate where I live), and would not cure the access issue of side by sides. Glassing is relatively cheap and I can do it myself, although staggering requires a lot of complimentary stuff like extended driveshafts, etc...
Any inputs will be appreciated!
I have a 38' Scarab Thunder on which I will rebuild the transom and engine room stringers next year. Looking down at the engines I realize that there's so much room in front of the Engines that if I extend the engine compartment by making a 20" notch (and move the transom back 20") it will be possible to mount the engines in a staggered configuration rather than side by side (the way it looks today). There are a number of reasons this could be a great advantage:
+ Most of the advantages of staggered engines (More room to work on the engines, Drives closer to the center = better propeller grip with lower mounting height, More weight moved closer to the centerline, etc)
+ A 20" notch enabling the x-dimension to be raised, although the drives will be deeper down towards the V (higher top speed)
+ Better angle of attack for the drives to work with (easier to trim the boat, easier to get on plane, and a higher top speed)
+ Still the same cockpit space, as I will only use the existing space in front of the engines
+ No shifting of the COG, as the extension would be in the shape of a notch
There are also a number of negatives of course:
- More work
- Less maneuverability when docking
- The possible risk of unpredicted negatives in handling, as this has not been done previously...
What do you think? Should I do it, or should I stick to just rebuilding everything the way it looks, and follow the old saying "If it ain't broken, don't fix it"...?
The biggest benefits in my world would be accessibility. Extension boxes and short lowers cost to much (due to import taxes and a poor dollar exchange rate where I live), and would not cure the access issue of side by sides. Glassing is relatively cheap and I can do it myself, although staggering requires a lot of complimentary stuff like extended driveshafts, etc...
Any inputs will be appreciated!
#2
Registered
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I like a guy who is willing to innovate and try things no one has done before. If you think you have a good plan, I say go for it.
#4
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My exhaust? This should be the least problem, but since you are asking:
I have stock 496 engines with stock manifolds and risers. Behind these there are 4" rubber hoses (as in most boats of this kind), and then a couple of custom made H-pipes with downturns and a special type of external choice that I made myself. Works well, and is really effective. The best part is that I can chose from silent mode or noisy mode when cruising at high speed without having the exhaust pass through some pipe the size of a milkshake straw, thus (hopefully) extending the life of the valvetrain and head gaskets...![Smilie](/forums/images/smilies/smile.gif)
Rebuilding to staggered would present a new challenge in building a new type of external silent choice exhaust, which could be really interesting!
I have stock 496 engines with stock manifolds and risers. Behind these there are 4" rubber hoses (as in most boats of this kind), and then a couple of custom made H-pipes with downturns and a special type of external choice that I made myself. Works well, and is really effective. The best part is that I can chose from silent mode or noisy mode when cruising at high speed without having the exhaust pass through some pipe the size of a milkshake straw, thus (hopefully) extending the life of the valvetrain and head gaskets...
![Smilie](/forums/images/smilies/smile.gif)
Rebuilding to staggered would present a new challenge in building a new type of external silent choice exhaust, which could be really interesting!
#6
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Location: Ontario, OH
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How do you intend to do the notch? Usually the notch is cut into the transom, sounds like you are trying to leave the "notch" at its current location, and planning on moving the transom back. That is a big endeavor, as you would need to extend the top deck, and the sides as well.
http://www.offshoreonly.com/forums/c...flat-deck.html
http://www.offshoreonly.com/forums/c...flat-deck.html
#7
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YOU need to work with someone who has experience in this type of work...first, you don't move the transom back, and LOWER mounting height? I say you are opening a can of worms if you don't have experience with this stuff. And i believe there are a few 38' Scarab's with Staggered engine configurations.
hmmmmmm, good luck?!?
hmmmmmm, good luck?!?
#8
Neno the mind boggler
![](https://www.offshoreonly.com/forums/images/icons/prop.gif)
![Default](/forums/images/icons/icon1.gif)
YOU need to work with someone who has experience in this type of work...first, you don't move the transom back, and LOWER mounting height? I say you are opening a can of worms if you don't have experience with this stuff. And i believe there are a few 38' Scarab's with Staggered engine configurations.
hmmmmmm, good luck?!?
hmmmmmm, good luck?!?
Will a 20" notch be asking for trouble on a 90's 38' Scarab Thunder with standard Bravo 1's?
I have a 38' Scarab Thunder on which I will rebuild the transom and engine room stringers next year. Looking down at the engines I realize that there's so much room in front of the Engines that if I extend the engine compartment by making a 20" notch (and move the transom back 20") it will be possible to mount the engines in a staggered configuration rather than side by side (the way it looks today). There are a number of reasons this could be a great advantage:
+ Most of the advantages of staggered engines (More room to work on the engines, Drives closer to the center = better propeller grip with lower mounting height, More weight moved closer to the centerline, etc)
+ A 20" notch enabling the x-dimension to be raised, although the drives will be deeper down towards the V (higher top speed)
+ Better angle of attack for the drives to work with (easier to trim the boat, easier to get on plane, and a higher top speed)
+ Still the same cockpit space, as I will only use the existing space in front of the engines
+ No shifting of the COG, as the extension would be in the shape of a notch
There are also a number of negatives of course:
- More work
- Less maneuverability when docking
- The possible risk of unpredicted negatives in handling, as this has not been done previously...
What do you think? Should I do it, or should I stick to just rebuilding everything the way it looks, and follow the old saying "If it ain't broken, don't fix it"...?
The biggest benefits in my world would be accessibility. Extension boxes and short lowers cost to much (due to import taxes and a poor dollar exchange rate where I live), and would not cure the access issue of side by sides. Glassing is relatively cheap and I can do it myself, although staggering requires a lot of complimentary stuff like extended driveshafts, etc...
Any inputs will be appreciated!
I have a 38' Scarab Thunder on which I will rebuild the transom and engine room stringers next year. Looking down at the engines I realize that there's so much room in front of the Engines that if I extend the engine compartment by making a 20" notch (and move the transom back 20") it will be possible to mount the engines in a staggered configuration rather than side by side (the way it looks today). There are a number of reasons this could be a great advantage:
+ Most of the advantages of staggered engines (More room to work on the engines, Drives closer to the center = better propeller grip with lower mounting height, More weight moved closer to the centerline, etc)
+ A 20" notch enabling the x-dimension to be raised, although the drives will be deeper down towards the V (higher top speed)
+ Better angle of attack for the drives to work with (easier to trim the boat, easier to get on plane, and a higher top speed)
+ Still the same cockpit space, as I will only use the existing space in front of the engines
+ No shifting of the COG, as the extension would be in the shape of a notch
There are also a number of negatives of course:
- More work
- Less maneuverability when docking
- The possible risk of unpredicted negatives in handling, as this has not been done previously...
What do you think? Should I do it, or should I stick to just rebuilding everything the way it looks, and follow the old saying "If it ain't broken, don't fix it"...?
The biggest benefits in my world would be accessibility. Extension boxes and short lowers cost to much (due to import taxes and a poor dollar exchange rate where I live), and would not cure the access issue of side by sides. Glassing is relatively cheap and I can do it myself, although staggering requires a lot of complimentary stuff like extended driveshafts, etc...
Any inputs will be appreciated!
I have played with this idea many many times when I started looking for a 38 Excel, ended up getting a 38 Thunder and still tossed it around but ultimately I dont want to give up cockpit space required to do it. I even entertained the thought of just lengthening the boat at the transom, which is do-able but extremly advanced. I would still love to do it but to much to give up.
__________________
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
#10
![Default](/forums/images/icons/icon1.gif)
How do you intend to do the notch? Usually the notch is cut into the transom, sounds like you are trying to leave the "notch" at its current location, and planning on moving the transom back. That is a big endeavor, as you would need to extend the top deck, and the sides as well.
YOU need to work with someone who has experience in this type of work...first, you don't move the transom back, and LOWER mounting height? I say you are opening a can of worms if you don't have experience with this stuff. And i believe there are a few 38' Scarab's with Staggered engine configurations.
hmmmmmm, good luck?!?
hmmmmmm, good luck?!?
correct, I have seen several factory staggered early eighties 377's (essentially a raised flat deck 38 but the same hull as all straight bottom 38 Scarabs. Never seen anything newer then about an 82 though.
I have played with this idea many many times when I started looking for a 38 Excel, ended up getting a 38 Thunder and still tossed it around but ultimately I dont want to give up cockpit space required to do it. I even entertained the thought of just lengthening the boat at the transom, which is do-able but extremly advanced. I would still love to do it but to much to give up.
I have played with this idea many many times when I started looking for a 38 Excel, ended up getting a 38 Thunder and still tossed it around but ultimately I dont want to give up cockpit space required to do it. I even entertained the thought of just lengthening the boat at the transom, which is do-able but extremly advanced. I would still love to do it but to much to give up.
![Smilie](/forums/images/smilies/smile.gif)
Last edited by Scarab Viking; 11-18-2015 at 04:19 PM.